This invention pertains to the field of electrical power systems, and more specifically to a system for remedying electrical power system instability.
Traditionally, electric utilities utilize complex system models of electrical power systems to examine thousands of simulated events that have the potential to cause reliability problems in delivering electricity to customers. One event that causes problems for systems having connected generation in different geographic areas is transient instability. For example, power swings caused by faults on transmission lines can result in synchronism loss (out-of-step) between electrical power systems. A swing relay is typically installed to detect such power swings. A modeling system instructs the swing relay to take appropriate action when synchronism loss is detected. The swing relay can attempt to remedy the power swings by running back generators or tripping generators offline to restore the electrical power systems to a stable state.
Referring to FIG. 1, there is shown a flowchart of a prior art monitoring system 100 for monitoring electrical power system stability. System status data 102 is compared with a simulated model 104 of instability and a result is produced. The result of the comparison is evaluated 106 to determine if a parameter or a criterion of the model has been violated. If a parameter or criterion has been violated 106, then a corrective action instruction 108 is transmitted to maintain system stability. The corrective action instruction 108 can be, for example, a generator rollback or a generator trip based upon the simulated model.
There are deficiencies in the prior art systems. For example, there is a delay inherent in the system because the simulated models require time consuming calculations to instruct the swing relay. This delay can cause a system crash with attendant blackouts. Also, the modeled events cannot cover all possible real-world events and thus can leave the electrical system vulnerable to non-predicted impact events that can cause power outages, blackouts or brownouts.
Accordingly, there is a need for a system for stabilizing electrical power systems that identifies impact events and quickly responds to the impact event in real-time.